Elastomer-silica pigment masterbatches and production processes relating thereto

ABSTRACT

CURBING OF SILICA PIGMENT LOSSES AND THE PROMOTION OF UNIFORMITY OF PRODUCT IN THE PREPARATION OF AN ELASTOMERSILICA PIGMENT MASTERBATCH ARE EFFECTED (A) BY COMBINING (1) AN AQUEOUS SLURRY OF HYDRATED SILICA PIGMENT PRECIPITATE WHICH HAS A BOUND ALKALI CONTENT, WHICH HAS BEEN PREPARED BY PRECIPITATION FROM AN AQUEOUS ALKALI METAL SILICATE SOLUTION, AND WHICH HAS BEEN CONTINUOUSLY KEPT IN AN AQUEOUSLY WET STATE WITHOUT HAVING BEEN DRIED AFTER ITS PRECIPITATION - WITH OR WITHOUT ADDITION IN AQUEOUS SOLUTION OF (2) REACTANT SELECTED FROM THE MEMBERS OF GROUP (I) THE WATER SOLUBLE SALTS OF ALUMINUM AND ZINC, GROUP (II) THE WATER SOLUBLE SALTS OF ALKALINE EARTH METALS, GROUP (III) THE WATER SOLUBLE ACIDS AND GROUP (IV) COMBINATIONS OF ANY TWO OR MORE OF THE FOREGOING MEMBERS - WITH (B) AN ORGANIC SOLVENT DISPERSION OF ELASTOMER CONSISTING ESSENTIALLY OF NITROGENOUS POLYMER CONTAINING 0.1 TO 20% OF NITROGEN IN THE FORM OF GROUPS SELECTED FROM THE CLASS CONSISTING OF AMIDE PRIMARY, SECONDARY AND TERTIARY AMINE, AND QUATERNARY AMMONIUM GROUPS - WITH OR WITHOUT (3) CARBON BLACK AND/OR PROCESSING OIL - AND (B) REMOVING THE SOLVENT AND AQUEOUS PHASE AND RECOVERING THE RESULTING COMBINATION AS A MASTERBATCH. NEW PRODUCTS PREPARED BY THE PROCESS ARE ALSO CLAIMED.   D R A W I N G

Oct. 24, 1972 ELASTOMER-SILICA PIGMENT MASTERBATCHES AND PRODUCTION PROCESSES RELATING THERETO Original Filed Jan. 24, 1967 Aqueouply wet never dried silica pigment 0. w. BURKE. JR 3,700,619

(III) water soluble acids (IV) combinations of 2 or more members selected from groups (I) to (III) (1) Carbon black (c) and/or w/wo (2) Processing oil and/Or (E) I l G v Nitrogenous elastomer (D') dissolved in solvent (5') (s) organic solvent immiscible wi water Drying of coagulum (F) Combine (C) and (D) w/w Solvent Solvent removal yielding coagulum and aqueous serum (e.g. injecting (F) into hot water) Mechanical separation of aqueous serum from coagulum pigment employed Dry elastomer-silica pigment masterbatch incorporating essentially all the silica Serum essentially free of silica pigment United States Patent ELASTOMER-SILICA PIGMENT MASTERBATCHES AND PRODUCTION PROCESSES RELATING THERETO Oliver W. Burke, In, Fort Lauderdale, Fla.

(1510 SW. 13th Court, Pompano Beach, Fla. 33061) Continuation-impart of applications Ser. No. 798,215 and Ser. No. 798,216, both Sept. 16, 1968, now abandoned,

which are divisions of application Ser. No. 611,250,

Jan. 24, 1967, now Patent No. 3,523,096, which in turn is a continuation-in-part of applications Ser. No.

458,379 and Ser. No. 458,420, both May 24, 1965, both now abandoned, and Ser. No. 479,806, Aug. 16, 1965,

now Patent No. 3,401,017. This application July 16,

1970, Ser. No. 55,472

Int. Cl. C08c 11/10; C08k N08 US. Cl. 26033.6 A0 9 Claims ABSTRACT OF THE DISCLOSURE Curbing of silica pigment losses and the promotion of uniformity of product in the preparation of an elastomersilica pigment masterbatch are effected (a) by combining (1) an aqueous slurry of hydrated silica pigment precipitate which has a bound alkali content, which has been prepared by precipitation from an aqueous alkali metal silicate solution, and which has been continuously kept in an aqueously wet state without having been dried after its precipitationwith or Without addition in aqueous solution of (2) reactant selected from the members of Group (I) the water soluble salts of aluminum and zinc, Group (II) the water soluble salts of alkaline earth metals, Group (III) the water soluble acids and Group (IV) combinations of any two or more of the foregoing members-with (b) an organic solvent dispersion of elastomer consisting essentially of nitrogenous polymer containing 0.1 to 20% of nitrogen in the form of groups selected from the class consisting of amide primary, secondary and tertiary amine, and quaternary ammonium groupswith or without (3) carbon black and/or processing oiland (b) removing the solvent and aqueous phase and recovering the resulting combination as a masterbatch. New products prepared by the process are also claimed.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of copending applications Ser. Nos. 798,215 and 798,216, filed Sept. 16, 1968, now abandoned as divisions of application Ser. No. 611,250, filed Jan. 24, 1967, now US. Pat. 3,523,096 said application Ser. No. 611,250 having been a continuation-in-part of earlier applications Ser. No. 458,420, filed May 24, 1965, (now abandoned); Ser. No. 458,379, filed May 24, 1965, (now abandoned); and Ser. No. 479,806, filed August 16, 1965, (now US. Patent 3,401,017), the disclosures of all of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION (1) Field of the invention The field to which this invention pertains is the preparation of masterbatches from solvent dispersions of elastomers and aqueous slurries of precipitated silica pigment.

BRIEF DESCRIPTION OF THE DRAWING The single figure of the drawing is a block-diagram illustrative of the process aspect of the invention.

SUMMARY OF THE INVENTION It is known to those skilled in the art to prepare hydrated silica pigment for the reinforcement of rubber by 3,700,619 Patented Oct. 24, 1972 "ice precipitation from aqueous solutions of alkali metal silicates with the aid of carbon dioxide, and to carry out such precipitation in manners to avoid the formation of gelatinous masses(i.e. the formation of silica gel)-and to promote the precipitation of a silica pigment in finely divided form (i.e. in particles in the reinforcing size range of about 0.015 to about 0.150 microns, preferably 0.02 to 0.06 microns) and to recover the pigment from the resulting wet silica pigment by filtration, washing and drymg.

The wet silica pigments formed by precipitation from alkali metal silicate solutions with the aid of carbon dioxide have a bound alkali content in the range of about 0.1 to 10% by weight as Na O, and upon being dried in this state form aggregates, from the pigment particles of reinforcing size, which aggreates are of much greater than reinforcing size and will not adequately disperse (i.e. break down into particles of reinforcing size) when incorporated into rubber either by dry compounding or latex compounding.

When one treats such alkaline wet silica pigments with water soluble salts of alkaline earth metals, e.g. calcium salts, to substantially replace the bound alkali metal of the silica, the resulting pigment, when dried, still evidences the formation of aggregates of greater than reinforcing size, which do not adequately disperse in the rubber.

When one treats the alkaline wet silica pigments with the Water soluble salts of aluminum and/or zinc, to substantially replace the alkali metal content thereof, the resulting acidic pigment, when dried, disperses to a greater extent in rubber, evidencing less aggregation than the neutral and alkaline products referred to above.

Finally, when one renders the wet silica pigment strong- 1y acidic, by treatment with sulfuric acid and drying, the resulting strongly acidic product is more readily dispersible in rubber, and exhibits minimum aggregation; however, such highly acidic pigments are not practicable for use in the reinforcement of rubbers, since their acidity adversely efiects vulcanization thereof.

Thus the drying of the wet silica pigment in alkaline, neutral, and moderately acidic states, in each instance causes the formation of aggregates of pigment particles to a greater or lesser degree which aggreation prevents adequate dispersion of the dry pigment in the rubber; the formation of these aggregates by the drying of the pigment is irreversible; and they remain mostly as aggregates that do not disperse in the rubber either by dry compounding or latex compounding.

This invention is based on the premise that uniformity of an elastomer-pigment masterbatch depends both on obtaining incorporation of a measured quantity of pigment in the masterbatch (e.g. avoiding loss of pigment in the serum in wet masterbatching) and adequate dispersion of the pigment in the elastomer in particles of reinforcing size (e.g. minimizing the pigment aggregation problem); and the present invention provides a process for accomplishing these ends by forming the masterbatch from aqueously wet hydrated silica pigment precipitate having a bound alkali content of 0.1 to 10% by weight as Na O; which has been prepared by precipitation from an aqueous solution of alkali metal silicate with the aid of carbon dioxide; and which has continuously been maintained in an aqueously wet state after its precipitation without having been dried therefrom; and which is combined with an elastomer dispersion in the still aqueously wet state, with special provisions for avoiding loss of pigment in the aqueous serum and promoting uniformity of product in the masterbatch.

Thus the present invention provides a simple and etficient process for the curbing of silica pigment losses and the promotion of uniformity of product in the preparation of masterbatches of measured silica pigment content. This process employs a solvent dispersion of elastomer and an aqueous slurry of low cost precipitated silica pigment having a bound alkali content. As shown in the drawing, the process consists essentially in (A) Providing to 100 parts by weight, dry basis, of aqueously wet hydrated silica pigment precipitate which has a bound alkali content in e range of 0.1 to by weight as Na O; which has been prepared by precipitation from an aqueous solution of alkali-metal silicate with the aid of carbon dioxide; and which has continuously been maintained in an aqueously wet state without having been dried therefrom after its precipitation;

(B) Providing, when used in step (C), reactant selected from the class consisting of the members of the following groups: Group (I), the water soluble salts of aluminum or zinc; Group (H), the water soluble salts of the alkaline earth metals; Group (III), the water soluble acids; and Group (IV), combinations of any two or more members of the foregoing groups;

' (C) Combining the wet silica pigment provided by step (A) with from 0 to at least a stoichiometric equivalent, based on the alkalinity of the silica pigment, of reactant provided by step (B); thereby to provide a wet silica pigment for use in step ('F);

(D) Providing an organic solvent dispersion containing 100 parts, dry basis by weight, of nitrogenous elastomer, said elastomer (D') containing 0.1% to by weight of nitrogen in the form of substituent groups selected from the primary amine, secondary amine, tertiary amine, quaternary ammonium, and amide groups and being essentially free of hydroxyl groups; and said solvent (8') being essentially water immiscible;

(F )-(F') Intimately mixing (1) the Wet silica pigment provided by step (A), (2) from 0 to 75 parts by weight of carbon blackfrom (E)-with the limitation that the total of silica pigment and carbon black, dry basis, not exceed 80 parts by weight and (3) from 0 to 45 parts by weight of processing oil-from (E)--, and (4) the solvent dispersion of nitrogenous elastomer provided by step (D), and

(G)-(L) Separating the volatiles from the resulting masterbatch, e.g. by volatilizing the solvent as at (G) followed by mechanical separation of the aqueous silica from the coagulum as at (I), and washing and drying of the coagulum as at (K) to yield the masterbatch (L).

Under these conditions the steps prior to the recovery render the serum resulting from the coagulation essentially free of silica pigment, thus assuring a uniform silica pigment content in the masterbatch. The achievement of this desideratum is evidenced by the fact that when the coagulum is mechanically removed from the serum, the serum is found to be essentially free of silica pigment, as indicated at (I in the drawing.

In particular embodiments of the invention the silica pigment may be treated with reactant (B) before blending with the nitrogen group containing elastomer (D), and may be combined therewith in alkaline, essentially neutral, or acidic form, and the elastomer may contain particular ones of the designated nitrogen groups, and in the following description of preferred embodiments, Examples 1-9, 19-25, 45-48, 53-56, 65-66, 71-73, 78- 81, and 86-89 disclose suitable procedures for preparing the aqueous dispersion or latex of amine, amide or quaternary ammonium group containing interpolymers including copolymers and graft polymers; and Examples 10-18, 26-44, 49-52, 57-64, 67-70, 74-77, 82-85 and 90-101 illustrate the practice of the invention with aqueous dispersions of polymers and treated and untreated wet silica pigments.

The nitrogenous elastomer (D) is dissolved in solvent-which may be recycled solvent (S)and said solvent itself, or as an azeotrope with water, preferably has a boiling point lower than that of water at atmospheric pressure, and the viscosity of the elastomer-solvent dispersion (i.e. solution) preferably is selected in the range of 5,000 to 50,000 centipoises, to facilitate the intimate mixing of the nitrogenous elastomer-solvent solution and the treated or untreated silica pigment aqueous slurry.

The silica-elastomer masterbatch recovery is effected by separating the volatiles from the coagulum, preferably in two steps (G) and (I) when the solvent or its aqueous azeotrope can be volatilized in step (G) prior to separation of the solids from the remaining aqueous phase in step (I). The volatilizing of the solvent, step (G) to convert the mixture (F, F) to coagulum and aqueous serum may be effected by running the dispersion (from F) into hot water. The greater part of the separation of the coagulum from the aqueous serum in step (I) is preferably effected by mechanical dewaterin-g, e.g. filtration, decanting, centrifuging, etc., to reduce the heat required for final drying (K) of the masterbatch (L). The serum removed by mechanical de-watering is found to be essentially free of silica pigment as indicated at (J) in the drawing and the dry elastomer-silica pigment masterbatch (L) thus incorporates essentially all of the silica pigment employed (in F). The process thus curbs silica losses and assures a uniform silica pigment content in the masterbatch.

In different embodiments or species the invention is applicable to producing masterbatches from the aqueous slurry of silica pigment with various categories of the nitrogenous elastomer or combinations thereof, containing from 0.1 to 20%, preferably /2 to 5%, of nitrogen, by weight, in the form of primary and/or secondary and/or tertiary amine groups and/or quaternary ammonium groups. In these several categories the dispersion (i.e. solution) of elastomer may have a concentration of from 5 to 50%, preferably 10 to 30%, dry solids by weight. Thus:

(1) In a first embodiment the invention provides a masterbatch from (a) aqueous silica slurry and (b) a soltuion of nitrogenous elastomer which has been prepared (l) by emulsion polymerization (2) of ethylenically unsaturated monomer material having amide and/ or primary, secondary, and/or tertiary amine and/or quaternary ammonium groups with (3) other ethylenically unsaturated elastomer forming monomer material, e.g. conjugated diene monomer material such as butadiene, isoprene, chloroprene and the like, alone or in various combinations with each other and/or with other vinylidine monomer material copolymerizable therewith e.g. styrene, acrylonitrile, etc.

(2) In a second embodiment, the invention provides a masterbatch from (a) aqueous silica pigment slurry and (b) a solution of a nitrogenous graft polymer which has been prepared from a precursor elastomer in latex form by latex grafting with the ethylenically unsaturated monomer material having primary and/or secondary and/or tertiary amine and/or quaternary ammonium groups and/or amide groups.

(3) In a third embodiment, the invention provides a masterbatch from (a) aqueous silica pigment slurry and (b) a solution of graft polymer elastomer which has been prepared from a precursor polymer in solution form, by solution grafting with the ethylenically unsaturated monomer material having amide and/or primary, secondary and/or tertiary amine groups and/or quaternary ammonium groups, the precursor elastomer grafted in solution being one which was prepared by aqueous emulsion polymerization.

(4) In a fourth embodiment, the invention provides a masterbatch from (a) aqueous silica slurry and (b) a solution of graft polymer elastomer which was prepared from a precursor polymer in solution form, by solution grafting with the ethylenically unsaturated monomer material having amide and/or primary, secondary and/or tertiary amine and/or quaternary ammonium groups, the

precursor elastomer itself having been prepared by anhydrous solution polymerization.

For convenience of reference and comparison, the foregoing embodiments or species are tabulated in Table A, which shows: Species I(A) in which the amine group containing monomer is copolymerized with elastomer forming monomer or monomer mixture, e.g. by emulsion polymerization (Col. 2) with conventional catalysts therefore, and the resulting elastomer solids are recovered and dissolved to form a solution (Col. of the nitrogenous elastomer. Species I(Q) which the nitrogen group is a quaternary ammonium group derived either (a) by similarly emulsion copolymerizing an ethylenically unsaturated quaternary ammonium group containing monomer; or (b) by similarly emulsion copolymerizing a tertiary amine group containing monomer-as in I(A), Col. 2and quaternizing the resulting elastomer in the aqueous phace (Col. 4); or (c) by similarly emulsion copolymerizing a tertiary amine group containing monomer and recovering and dissolving the resulting precursor polymer-as in I(A), Cols. 2 and 5--and quaternizing the tertiary amine elastomer in the solution (Col. 8). Species II(A), wherein a precursor homopolymer or copolymer elastomer latex is prepared, e.g. by emulsion polymerization (Col. 1 or 2), latex grafted with amine monomer (Col. 3) and recovered and dissolved (Col. 5) to form the nitrogenous elastomer solution. Species II(Q), wherein the precursor polymer is prepared and grafted in the same manneras in II(A)but with a quaternary ammonium monomer (Col. 3), or with a tertiary amine monomer (Col. 3) followed by quaternizing in the latex state (Col. 4), or with a tertiary amine monomer (Col. 3) followed by recovery, solvation, and quaternizing in solution (Col. 8). Species III(A) and (Q), wherein the precursor polymers are formed by emulsion polymerization (Cols. l or 2), and are recovered and dissolved in solvent (Col. 5) and then grafted in solution with the amine or quaternary ammonium monomer (Col. 7), or alternatively with the tertiary amine monomer (Col.7), followed by quaternization thereof in solution (Col. 8). Species IV(A) and (Q), wherein the elastomer, e.g. butyl rubber, or ethylene-propylene elastomer, or the like, is prepared in a solution polymerization (Col. 6), and grafted in solution (usually in a different solvent) with the amine or quaternary ammonium monomer (Col. 7), or altarnetively with the tertiary amine monomer (Col. 7) followed by quaternizing thereof in solution (Col. 8).

formation of masterbatches therewith with solvent dispersions of certain nitrogenous elastomers.

Elastomers To maintain clear lines of division from other copending applications, the elastomer solutions employed in the present invention are limited to those prepared from C to C ethylenically unsaturated monomers with amide, amine or quarternary ammonium groups with or without other C to C ethylenically unsaturated monomers copolymerized or graft polymerized therewith, and exclude solutions of elastomeric polymers not having such groups, or having such groups in combination with hydroxyl groups.

Among the nitrogenous elastomers especially suitable for use in preparing the silica containing masterbatch are the butadiene copolymers of the aminoacrylates and the vinyl pyridines with or without other vinylidene (including vinyl) monomers such as: the butadiene/Z-vinyl pyridine copolymers, the butadiene/4-vinyl pyridine copolymers, the butadiene /2-methyl-5-vinyl pyridine copolymers, the butadiene/diethylaminoethyl methacrylate copolymers, the butadiene-dimethylaminoethyl acrylate copolymers, the butadiene/styrene/monoalkylaminoalkyl and dialkylaminoalkyl acrylate and methacrylate copolymers, the butadiene/acrylonitrile/vinyl pyridine copolymers, the butadiene/acrylonitrile/alkylaminoalkyl acrylate and methacrylates and such polymers in which the amine monomer is replaced with an amide monomer such as acrylamides or methacrylamide.

When the nitrogenous elastomer contains tertiary amine groups, such groups may be quaternized as aforesaid.

The precursor elastomers which can be grafted and employed in solution in accordance with the present invention include diene homopolymer rubbers such as polybutadiene, polyisoprene, polychloroprene; diene copolymer rubbers such as the copolymers of diene monomers and monomers containing and copolymerizable therewith through a single ethylenically unsaturated group, eg butadiene-styrene, butadiene-acrylonitrile or methacrylonitrile, butadiene-acrylates or methacrylates; and rubbery copolymers of hydrocarbon monomers with polar vinylidene (including vinyl) monomers, as well as mixtures and combinations thereof (excluding hydroxy monomers).

Precursor polymers prepared by solution polymerization and suitable for preparation of the graft nitrogenous polymers include but are not limited to elastomers prepared in anhydrous solvent systems, eg with the aid of TABLE A Categories of Nitrogenous Elastomer Preparations Solution Aqueous polymerization (latex) Emulsion polymer (5) b Homo- Co- Grafting Quater- Anhydrous Grafting Quater- Categories polymer (1) polymer (2) monomer (3) nizing (4) polymer (6) c monomer (7) nizing (8) I(A) Amine (5) (Q) Quaternary (4) i (5) (8) I(A) (1) 0r---- )-A1I1 (4) (8) I (Q)---. n (3)-.

Anhydrous polymerization IIT(A) ..do..... (2). (5) (7)Amine (8) III(Q) (2)--.. (5) (7)Q,uaternizlng (A)----- (7)Ami (8) (Q) (6) (7)-Quaternizing B Polymers containing amide groups may be prepared in a manner like those containing amine groups.

b Prepared by emulsion polymerization. 8 Prepared by anhydrous polymerization.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention avoid the use of organic additives such as tetraethylene pentamine, glue, gelatin, casein, etc., which increase the cost and may elfect the curing properties of the masterbatch. The invention generally may be used to improve wet silica masterbatching and masterbatches using any alkaline slurry of wet silica pigment containing bound alkali which has not been subjected to drying, and is applicable to the catalyst systems employing metal alkyls and/or transition metal halides. In certain of these systems after the polymerization of the olefin and/ or diolefin is complete and the catalyst has been removed, the elastomer is already in solvent solution or can readily be transferred to a solvent solution suitable for grafting with the nitrogenous monomers to yield the graft nitrogenous polymers employed in the practice of this invention. Such precursor polymers prepared by solution polymerization include, but are not 5 limited to, elastomers from olefins and/or cyclic olefins and/or cyclic diolefins and/or dicyclic diolelns including ethylene-propylene copolymers, ethylene-propylene terpolymers, ethylene-butylene copolymers and terpolymers, and butadiene-monoolefin interpolymers and the like.

The elastomers prepared by free radical catalyzed polymerization, e.g. by emulsion polymerization, can have the nitrogenous groups introduced thereinto by graft polymerization to the precursor polymer; or may be initially formed as nitrogen containing polymers by copolymerization with the nitrogenous monomers. The elastomers prepared by anhydrous solution polymerization, e.g. using Ziegler type catalyst, can be grafted with the nitrogenous inonomers, in solution, with the aid of free radical cataysts.

Nitrogenous polymer solvents In the practice of this invention the nitrogenous polymer is in solution. It is often necessary to employ a solvent system to dissolve the said polymers as for example toluene and butanol. Certain polar solvents such as alcohols have the ability to hydrogen bond with amine or quaternary ammonium groups and thus break up the intermolecular hydrogen bonding of the polymer molecules and permit solution in a solvent such as toluene. In selecting the solvent the volatile hydrocarbon or halohydrocarbon, or halocarbon solvents are desirable, e.g.: butane, pentane, hexane, cyclohexane, methylene chloride, carbon tetrachloride, and the like.

Monomers Typical of the primary, secondary and tertiary C to C amine monomers which may be employed for forming nitrogenous elastomer, e.g. by emulsion copolymerization or by emulsion or solution graft polymerization, are: the amino olefinic ethers, such as the amino vinyl others including aminoethylvinyl ether, N-ethylaminoethylvinyl ether, aminopropylvinyl ether, N-methylaminoethylvinyl ether, N,N-diethylaminoethylvinyl ether and the like; the olefinic amines, such allyl amines as N,N-dimethyl allylamine, N,N-diethyl, dipropyl, dibutyl, diisobutyl, diphenyl and similar allylamines and N-allyl morpholine, N-allyl-pyridine, N-allyl-ethyleneirnine and the like; basic nitrogen containing esters of olefinic acids, such as aminocyclohexyl methacrylate, ,e-piperidyl-N- ethyl methacrylate, B-morpholine-N-ethyl methacrylate, N-methacrylyl morpholine, N-methacrylyl thiomorpholine, N-methacrylyl piperidines, N-acrylyl morpholine, N- acrylyl thiomorpholine, N-acrylyl piperidine and the like; the acrylamino substituted acrylic and a and fi-acrylic acid esters, such as the methyl, ethyl, propyl and the like alkyl esters of a-acetoacrylate, a-N-butylaminoacrylate and the like; the vinyl pyridines, such as 2-vinyl pyridine, 3-vinylpyridine, 4-viny1pyridine, 2-vinyl-5-ethyl pyridine, 2-methyl-5-vinylpyridine and the other ethyl and methyl isomers of vinylpyridine and the like.

Typical of the quaternary ammonium compound monomers are quaternization products of the above exemplified tertiary amines, obtained by reacting such amines with methyl chloride, methyl bromide, benzyl chloride, benzyl bromide, and other allyl and aryl halides, sulfonates, phosphates, and the like, e.g. toluene sulfate; examples of which include methacryloxyethyltrimethylammonium methylsulfate, fl-dimethylaminoethyl methacrylate, methyl a-diethylaminoacrylate, methyl nz-(N- methylanilino)-acrylate, methyl a-dibenzylaminoacrylate, methyl u-distearylaminoacrylate and the like.

Typical of the ethylenically unsaturated C -C amide monomers which may be employed in forming the copolymer or graft polymer elastomer employable in the present invention are the amides of acrylic acid and ccand p-substituted acrylic acids such as acrylamide, N- methylacrylamide, N-methylmethacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N-propylacrylamide, N-propylmethacrylamide, N-isopropylacrylamide, N-isopropylmethacrylamide, N-t.-butylacrylamide, N-t.-butylmethacrylamide, N-amylacrylamide, N-amylmethacrylamide, N-t.-octylacrylamide, N-decylacrylamide, N-phenylacrylamide, N-phenylmethacrylamide, N-o-tolylacrylamide, N-p-tolylacrylamide, N-naphthylacrylamide, N,N- dimethylacrylamide, N,N-diethylmethacrylamide, N,N- diethylacrylamide, N,N-dimethylacrylamide, N,N-methylethylacrylamide, N,N ethylmethylmethacrylamide and other N- monoand N,N-di-substituted unsaturated acid amides, e.g. where the substituent is alkyl C to C haloalkyl and the like.

Typically of the conjugated diene monomers which can be employed to form the copolymers or graft polymers used herein are the C to C hydrocarbon conjugated diene monomers such as butadiene-l,3, isoprene, piperylene, the hexadienes including 2,3-dimethylbutadiene, the halogen substituted C to C conjugated dienes such as chloroprene, the cyano substituted 0,, to C ,conjugated dienes such as 2-cyanobutadiene and the like.

In various of the examples, which are illustrative but not restrictive of the invention: (a) the hydrated silica pigment has a bound alkali content in the range of 0.1 to 10% by weight as Na O and has been prepared by precipitation from an aqueous solution of alkali metal silicate with the aid of carbon dioxide and said silica precipitate has been continuously maintained in the aqueous phase without having been dried after its precipitation; (b) the aqueous silica pigment is combined with from 0 to at least a stoichiometric equivalent based on the alkalinity of the silica pigment slurry, of reagent selected from the class consisting of the members of Group (I) the water soluble salts of aluminum or zinc; Group (II) the water soluble salts of the alkaline earth metals; Group (III) the water soluble acids and Group (IV) combinations of any two or more of such members.

The term water soluble acids as used herein designates the inorganic and organic acids which are water soluble both as free acids and in the form of alkali metal or ammonium salts. Examples of such acids are hydrochloric, sulfuric, nitric, phosphoric, formic, acetic, hydroxyacetic, the chloroacetic acids, propionic, oxalic, tartaric, citric, maleic, and the like.

In the examples, the combination of nitrogenous elastomer-solvent dispersion and silica pigment slurry was effected by intimate mixing in the high speed, high shear Waring Blendor. The removal of solvent from the intimate mixture was accomplished by dropping the said mixture into boiling water and the volatile solvent readily boiled off leaving a wet coagulum or wet crumb in the aqueous serum, which serum was free of silica or essentially free of silica.

Silica pigments containing residual alkali suitable for masterbatching in accordance with the present invention are usually precipitated by the gradual acidulation with the aid of carbon dioxide of aqueous sodium silicate solution.

Carbon black By the term carbon black as used herein is meant any carbon blacks suitable for use by the rubber industry and set forth under the title carbon blacks at pages 251 and 264 of the publication entitled Materials and Compounding Ingredients for Rubber, compiled by J. V. Del Gatto, published by Rubber World, 1968, and herein incorporated by reference, e.g. Philblack 0 (TM), Statex K (TM), Statex (TM), Kosmobile 77 (TM), Thermax (TM), and the like.

Processing oils The term processing oils as used herein is meant rubber processing material of both liquid and solid types (if required the solids types can be converted to the liquid state for use herein with the aid of solvent or plasticizer) and include the processing materials set forth under Plasticers and Softeners at pages 149 to 214 of the publication entitled Materials and Compounding Ingredients for Rubber, compiled by J. V. Del Gatto, published by Rubber World, 1968, and herein incorporated by reference and among the types of processing materials especially suitable for use in this invention are (a) the coal tar oils and pitches e.g. Bardol (TM), Bardol B (TM); (b) the asphalts, e.g. BRH #2 (TM); (c) the petroleum oils including the paraffinic, naphthenic, aromatic, and highly aromatic categories, which are commercially available under trademark designations, Sunpar (TM), Sundex (TM), Sunthene (TM), Circosol (TM), and Shellfiux (TM) oils, and the like, such as Circosol 2XH (TM), Sundex 53 (TM), Shell SPX 97 (TM), Dutrex-20, -4l9, -726, -757, -787 (TM), and Califlux TT (TM) and other oils suitable for rubber compounding or the oil extension of synthetic rubber; (d) the coumarone-indene oils and resins, e.g. Cumar Resin RH, -P10, -T (TM); (e) the liquid ester type plasticizers, e.g. dibutyl phthalate, di-(2- ethylhexyl) phthalate, diglycol laurate, dibenzyl sebacate, tributoxyethyl phosphate, tricresyl phosphate and the like; (f) the phenol formaldehyde thermoplastic resins, e.g. Durez 12687, 12707 (TM) and the like; (g) the hydrocarbon resins, e.g. Neville-LX 782, -VX 125 (TM), Para- Flux, Para Resin 2457 (TM); (h) the hydrocarbon resincoumarone indene polymers, e.g. Picco Resins (TM); (i) the pine tars and pine tar oils, rosin and rosin oils, and tall oil and its derivatives, e.g. PT-l, PT-40l, PT-800 (TM); and the like.

EXAMPLES The following examples will serve to illustrate the invention in more detail:

Silica preparation and examples 1-110 The aqueous slurry of precipitated silica employed in Examples 10-40 was prepared in a manner similar to Example 9 of US. Pat. No. 3,250,594 except that the ratio of 41 B. commercial sodium silicate to water was approximately 1 to 4.5 by weight. The carbon dioxide was supplied to the sodium silicate with the aid of a single submerged combustion burner up to the appearance of the Tyndall effect and with two such burners thereafter. The use of the submerged combustion burners was according to U.S. Pat. No. 3,372,046. The silica product was filtered and washed to reduce the soluble salts to the range of l to 2% and the filter cake had a solids of approximately 10% by weight. The resulting aqueous silica slurry was designated wet alkaline silica pigment-I, and had a bound alkali content of about 1.5% by Weight as Na O, and a serum pH of about 8.5.

A portion of this alkaline silica slurry was acidified to a pH of 4.5 with dilute sulfuric acid and as a filter cake, with washing to a pH of about 7, had a solids of approximately 10% by weight. The resulting aqueous silica slurry was designated wet silica pigment-II.

The just described filter cakes having a solids content of about 10% by weight are embraced within the term wet silica pigment (which herein connotes aqueously wet silica pigment) as are wet pigments of more reduced water content which can be prepared by pressing the said filter cakes, or of augmented water content, e.g. slurries having less than 10% solids content, and the terms aqueously wet silica pigment or aqueously wet state, as employed herein are generic to all such conditions. Thus these terms as employed herein embrace aqueously wet silica pigment materials having a solids content in the range of about 1% to about solids, dry basis, by weight; however, for economy in the practice of the invention wet silica pigments of reduced water content (solids content 8 to 36%) are preferred.

10 To determine pigment quality a portion of wet silica pigment-II was dried at C., micropulverized and compounded as set forth in Table I hereof.

TABLE I Quantities Compound ingredients: (pts. wt.) Butadiene-styrene copolymer 100 a Cumar Resin RH (a trademark product).

The compound was aged over-night, re-milled and cured for 45 minutes at 287 F.

The physical test data for the Nulcanizate so prepared with the foregoing silica pigment is set forth in Table II hereof.

TABLE II Silica tested (in Hardness Tensile Modulus Elongation vulcanizate) (Shore A) (p.s.i.) (300%) (percent) Silica pigment-II 72 3, 530 1, 575

In the examples, in Tables III and IV, Examples 1 through 9, precursor butadiene-styrene copolymers produced by solution polymerization and precursor butyl type rubber are dissolved in solvents and solution grafted with amine type monomers.

In Tables V and VI Examples 10-18 aqueous silica pigment slurries having a bound alkali content are reacted with soluble aluminum and zinc salts and with sulfuric acid and then solution masterbatched with the solution elastomers having amine groups prepared according to Tables IIII and IV.

In Tables VII and VIIII Examples 19-25 the precursor butadiene-styrene copolymer and butyl rubber were solution grafted with amine monomers and quaternized to form the nitrogenous elastomer.

In Tables IX-XIII Examples 26-44 the elastomers with quaternary ammonium groups were combined with aqueous silica slurry treated with water soluble acids (Examples 2633) with water soluble aluminum and zinc salt reactants (Examples 26-33, 38, and 41-44) and with 'water soluble alkaline earth metal salt reactants (Examples 36 and 39-40) and without reactant treatment (Example 37).

In Table XIV Examples 45-48 provide soltuions of copolymers containing amine groups and in Table XV Examples 49-52 these active nitrogenous polymers in solution are blended with wet silica pigment which has been treated with aluminum sulfate as the selected reactant and the combination freed of solvent and dried to yield masterbatches.

In Table XVI Examples 53-56 the amine group containing elastomer in solution (Examples 45-48) is quaternized. In Tables XVII and XVIH Examples 57-64 there active nitrogenous polymers are masterbatched with treated silica.

In Table XIX Examples 65 and 66 is described the preparation of solutions of a graft polymer containing 1 1 amide groups and in Table XX Examples 67-70 masterbatches and preparation are described employing silica treated with reactant.

Table XXI Examples 71-73 provide a recipe and method for preparing a solution of copolymers having amide groups and Table XXII Examples 74-77 provide means of preparing the silica masterbatches with these nitrogenous elastomer solutions.

Table XXV Examples 86-89 provides examples of the preparation of a solvent solution of a copolymer containing amine groups.

in Table XXIII Examples 78-81, Table XXVI Examples 90-93, Table XXVII Examples 94-97 and Tables XXVIII Examples 98-101 exemplify the method and composition employing wet silica pigment and carbon black and/ or processing oil and mastenbatches from combinations thereof with the nitrogenous elastomer solutions hereof.

In certain of the examples the alkaline silica slurry is mixed with sutficient water soluble aluminum salt, zinc salt, alkaline metal salt and/or acid to react with substantially all of the bound and free alkali and thus reduce the aqueous slurry pH to 7.0 or lower.

It is preferable to employ a silica filter cake, with or without fluidizing by high shear working before or after treatment with reactant. This minimizes the water to be homogenized into the elastomer-solvent cement. Combining of the silica slurry and the cationic nitrogen elastomercement is carried out in a typical high speed, high shear mixer. The solvent is readily removed by injecting the homogenized mix into hot or boiling water. To facilitate recovery, solvents are employed which are immiscible with water and which themselves, or as their azeotropes, boil lower than water at atmospheric pressure or at higher or lower pressures if it is desirable to employ such.

The solvents employed in the examples are typical of the C to C hydrocarbon solvents, e.g. hexane, benzene and toluene, and of the C to C halocarbon and halohydrocarbon solvents, e.g. methylenechloride, and other members of such groups and mixtures thereof may be selected which are suitable for dissolving the cationic nitrogen elastomers concerned, e.g. butane, pentane, cyclohexane, heptane, octane, xylene, carbon tetrachloride, trichloroethylene, and oxygenated solvents immiscible with water.

The processes of the examples are adaptable for either continuous or batch production of the masterbatch. In those instances in which an oil-rubber-silica pigment masterbatoh is desired, up to about 45% of oil based on the elastomer is added to the elastomer-solvent cement, preferably with a small amount of ammonium hydroxide to aid dispersion of the oil and the elastomer cement and it will thus be understood that the masterbatch and elastomer dispersion contemplated by the invention may contain a minor proportion of oil. Similarly in the examples employing the same, any soluble aluminum salt may be substituted for the hydrated aluminum sulfate, e.g. aluminum ammonium sulfate or aluminum sodium sulfate, and the coagulant solution contemplated by the invention may thus comprise minor amounts of ammonium and/ or alkali metal salts without detriment to the process. Furthermore the elastomer cement and/or the aqueous dispersion of silica pigment and/or the aqueous reactant solution may contain a small proportion of ammonium hydroxide which appears in certain instances to facilitate practice of the invention. When carbon black is also to be included in the elastomer-silica pigment masterbatch, it may be incorporated as an aqueous slurry along with the slurry of the silica pigment.

In the following tabulations of Examples 1-101 the ingredients (A), (B), (C) etc. are listed in the order of their addition except where otherwise spectfically set forth. The masterbatches are conveniently prepared at room temperatures, however, elevated temperatures may be employed as to accelerate the masterbatch formation.

TABLE III Preparation of Nitrogenous Elastomer by Graft Polymerization in Solution (Parts by wt.)

Example (A) Polymer solution:

(a) Precursor polymer:

Butadiene-styrene 100 100 Butadiene-styrene 1 Isobutylene-isoprene 200 200 (b) Solvent:

Hexane 900 900 300 900 Toluene 300 (c) Solvation conditions:

Temperature, C 70 70 Time agitated, hrs 12 12 12 (B) Polymer solution grafting:

(a) Monomers:

z-vinyl pyridine 4-viny1 pyridine t.-Butylaminoethylmethacrylate 5 (b) Catalyst:

Cumene hydroperoxide 80% 2 4 3 2 Benzoyl peroxide Tetraethylenepentamine 1 (c) Polymerization conditions:

Temperature, C Time agitated, hrs

1 Solprene 300 (a trademark product) a normal viscosity, non-staining. solution polymerized random /25 copolymer of butadiene and styrene (milled).

1 glolgreue 1206 (a trademark product) same as (1) except otlow viscosity m e a Butyl rubber 268 (a trademark product) (milled).

TABLE IV Preparation of Nitrogenous Elastomer by Graft Polymerization in Solution (Parts by wt.)

(B) Polymer solution grafting:

(a) Monomers:

2-vinyl pyridine 5 t.-Butylaminoethylmethyacrylate. Diethylaminoethylmethacrylate Dimethylaminoethylacrylate. (b) Catalyst:

Cumene hydroperoxide Benzoyl peroxide Tetraethylenepentamine 2 (c) Polymerization conditions:

Temperature, C Time agitated, hrs 8 8 8 8 Solprene 1206 (a trademark product) a low viscosity, non-staining, solution polymerized random 75/25 copolymer of butadiene styrene (milled).

Z Butyl rubber 268 (milled).

TABLE V Silica-Nitrogenous Elastomer Masterbatch (Parts by wt.)

Example (A) Silica pigment slurry-treated: (a) Silica pigment slurry:

Alkaline silica pigment-I (pH=8.5) 50 50 50 50 Dry solids basis 10 6 5 5 5 Water 40 20 20 2O 20 (b) Reaetant-aqueous solution:

2% aluminum sulfate 1 36 2% zinc sulfat 15 2% sulfuric acid 8.5 8.5 Silicaslurry pH 5.0 6.5 7.0 7.0 8.6 (c) Treated silica pigment:

Filtered (X) X X D Filter cake 44 41 55 2% sulfuric (aqueous) 1.2 1. 2 H 5. 0 5. 0

p (B) Graft polymer solution:

(a) Polymer solution-Table III (concentration adjusted as indicated):

Example 1 Example Example TABLE V-Continued TABLE VIII Silica-Nitrogenous Elastomer Masterbatch (Parts by wt.) Preparing Polymers in Solut(il ;n {Vigh Qttiaternary Ammonium Groups er s y w Example Example 10 11 12 13 14 5 23 24 25 (b) Solvent:

"Pram (A) Polymer solution: Benzene.-. 25 (a) Precursor polymer: Antioxidant 3 0. 4 0.4 0.2 0. 2 0. 2 Isobutylene-isoprene 1 Combine (A) plus (B) in high shear blend- Ethylene-propylene terpolymer 2 60 50 er, time mixed, min 1 1 I 1 1 (b) Solvent:

(D) Solvent removal: Hexane 450 Boiling Water (X) X X X X Benzene.- 650 450 Silica separation into water hase... (0) Salvation conditions:

(E) Masterbatoh: Dried (105 C. (X) X X X X X Temperature C 70 70 70 Time agitated, hrs 12 12 12 1 Aluminum sulfate Alz(S04)3-14Hz0. (d) Organic peroxide: Cumene hydroperoxide (80%)-- 2 2 2 i Precipitate rewashed. (e) Conditions: 3 The antioxidant is 2,2-methylene-bis(4-methyl-fi-t-butylphenoD- Temperature C 90 90 90 4 Waring Blender (a trademark product). Time agitated, hrs 4 4 09 5 The silica-solvated graft polymer is dropped into boiling water to (B) Polymer graftingand quaternizing: vaporize the solvent and the silica-graft polymer masterbatch is recovered (a) M mers; from the aqueous serum and dried. 2-vinyl pyridine 3 None. 0)) ghtprithylaminoethylmethacrylete 3 3 a a ys sys em: TABLE VI Cumene hydroperoxide (80%) 1 1 1 Silica-Nltrogenous Elastomer Masterbatch (Parts by Wt.) tetl'?eth ylenepel lt amlne 1n benzene 4 4 4 (c) %0lymrl8tl0gl0ndltl0llsl 90 1 empera ure 90 90 Jfii... (d) aims agitated, hrse 14 14 14 16 1g uaternizing agen 15 17 glethyll blriimige- 5.4 3.6

A Silica i ment slurr -treated: emy E 8 sih aa pigment sliirr Quatemlzlng '3? Alkaline silica. pigment-I (pH 8.5) 50 50 50 50 T9H1Del'1 1t11!19 C 90 90 9 Dry solids basis 5 5 5 5 Time agitated 4 4 2 Water 20 20 20 0 (b) Reactant.aqueous Solution; Butyl rubber 268 (a trademark product) (imlled).

2% aluminum lfat 1 13 13 2 Nordel 1320, (a trademark product), a terpolymer of ethylene, pro- 2% w -1 acid g 5 pylene and a non-con ugated diene (milled). Silica slurry pH 5.0 5. 0 7.0 8.5

(c) Treated silica pigment: Filtered (X) X X X X TABLE IX (B) Graft polymer solution:

(a) f y solution table IV (concentration Masterbatcli Siliea-Elastomer Grafted With Quaternary Ammonium ad usted as indicated): Groups (Parts by wt.)

Example Example 9 1 26 27 28 29 Polymer content, dry l0 10 10 10 (b) Solvent: (A) Silica pigment slurry treated: tflne 25 20 (a) Silica pigment slurry: B n en 0 25 Alkaline silica pigment-I (pH 9.4) 200 200 200 200 Antioxidant 0.2 0.2 0. 2 0. 2 Dry solids basis 2o 20 20 20 Aqueous ammonia 5.6%. 4 3 5 watei- 50 5o 50 50 a p in high Shea blender:a (b) Reactant-aqueous solution:

Time mixed, m 2 2 2 10% suliuric acid- 6.8 6.8 6.8 e. s

(D) Solvent removal: Silica slurry, pH 7 7 7 7 Bq g Watelj X X X X (c) Treated silica pigment:

Silica separation into Water hase... Entered (X) X X X (E) Masterbatch: Dried 05 (X) X X X X Filter cake 162 162 162 162 (B) Solution polymer with quaternary ammonium 1 Aluminum sulfate A12(SO4)3- 14H20: g1'0up5 T3b1e VII; 1 The antioxidant is 2,2-methylene-b1s(4-methyl-6-t.-butylphen0l)- Example 19 400 a Waring Blender (a trademark product). Example 20 400 4 The silica-solvated graft polymer masterbatch is dropped into boiling Example 21 4 water to vaporize the solvent and the silica-graft polymer masterbatch Example 22 is recovered from the aqueous serum and dried. Polymer content 40 40 5 None- I i E da "1"" '1)"1i"21""" 2 6% 25% 5 en mg p us en er, min. TABLE VII (D) Solvent removal: 3 Preparing Polymers in Solution With Quaternary Ammonium Groups pl g in 2 X X (P t by t) Silica separation into water (E) Masterbatch: Dried (105 C.) (X) X X Example I The antioxidant 1S 2,2'-methyl-bis (4-methylene-6-t.-butylphenol).

19 20 21 22 2 Waring blender (a trademark product).

5 The silica-graft polymer masterbatch is dropped into boiling water A) Polymer l ti to vaporaize the solvent and the polymer-silica masterbatch is recoverde (a) Precusor polymer: Butadiene-styrene 50 50 50 50 from the aqueous serum and dried. (b) Solvent: Hexane 450 450 450 450 4 None. (0) Srolvationtcondigons: 70 70 70 7 empera ure TABLE X Time agitated, hrs 12 12 12 12 (d) Organic peroxide: Cumene hydroperoxide Masterbatch Sillca-Elastomer Grafted With Quaternary Ammonium 0 2 Groups (Parts by wt.) (e) Conditions:

Temperature C 90 90 90 90 Example Time agitated, hrs 4 4 4 4 (B) Polymer grafting and quaternizing: 30 31 32 33 (a) Monomers:

2-vinyl pyridene 3 3 (A) Silica pigment slurry treated: Dimethylaminoethylmethacrylate 3 3 (a) Silica pigment slurry: (b) Catalyst-system; Alkaline silica pigment-I (pH 9.4) 200 200 200 200 Cumene hydro eroxide (80%) 1 1 1 1 Dry solids basis 20 20 20 20 10% tetraethylene pentamine in benzene. 4 4 4 4 Water 50 50 50 50 (c) Polymerization conditions: (b) Resistant-aqueous solution.

Temperature C 90 90 90 90 1ll% sulfuric acid 6.8 6.8 6.8 6.8 Time agitated, hrs 14 14 14 14 Silica slurry. pH- 7 7 7 7 (d) Quaternizing agent: Treated Silica pigment Methyl bromide 5.4 3-6 Filtered (X) X X X X Benzyl chloride- 7.2.-..- 4. 8 Filter Cake 162 162 162 162 (e) Quaternizing conditions: (B) Solution polymer with quaternary ammonium Temperature C 90 90 90 90 groups-Table VIII: Time agitated, hrs 4 4 4 4 Example 23.-.- 400 Example 24.- 560 i Sulprene 300 (a trademark product) a normal viscosity, non-staining, Example 25 4 4 solution polymerized random /25 copolymer or butadiene and styrene Polymer 0n en 4 4 4 4 Antioxidant l 0. 8 0. 8 0. 8 0.8

(milled).

TABLE X-Contlnued l The antioxidant is 2,2-methylene-bis(4-methyl-6-t.-butylphenol).

1 Waring blender (a trademark product).

i The silica-graft polymer masterbatch is dropped into boiling water to vaporize the solvent and the polymer-silica masterbatch is recovered from the aqueous serum and dried.

TABLE XIII Silica-Elastomer Masterbatch (Parts by wt.)

Example (A) Silica pigment slurry:

(a) Silica pigment slurry:

Alkaline silica pigment-I (pH 8.5-9.5) 200 200 200 Dry solids basis 20 20 20 Water 100 100 100 (b) Reactant'aqeuous solution: 2% aluminum sul- 72 72 72 (c) Treated silica pigment:

Filtered (X) X Filter k (B) Solution pol er with qua groups-table vii Example 1 400 Example 20 400 Example 21 400 Polymer content dry solids 40 40 40 Benzene. 100 150 (C) Blending (A) plus (B): Blender, min. 1 (X) X X (D) Solvent removalz Boiling water (X) X X X Silica separation into water (E) Masterbatch: Dried (105 C.) (X) X X X 4 None.

TABLE XI Masterbatch Silica-Elastomer Grafted With Quaternary Ammonium Groups (Parts by wt.)

Example (A) Silica pigment slurry treatment:

(a) Silica pigment slurry:

Alkaline silica pigment-I (pH 9. 4) 200 200 200 200 Dry solids basis 20 20 20 20 Water 50 50 50 50 (b) Reactant-aqueous solution:

2% uminum suliate 72 2% zinc sulfate 2% magnesium sulfate (c) Treated silica pigment:

Filtered (X) X X X X Filter cake 164 170 160 206 (B) Solution polymer with quaternary ammonium groups-Table VII:

Example 19 400 Example 20-.. 400 Example 21... 400 Example 22 400 Polymer content 40 40 Antioxidant I 0 8 0. 8 0.8 0.8 (C) Blending (A) plus (B): Blender, min. 0 5 0.5 0.5 0.5 (D) Solvent removal: 4

Boiling water (X) X X X X Silica separation into watc (E) Masterbatch: Dried (105 C.) (X) X X X X r Aluminum sulfate A12(SO4)a-14H2O Antioxidant 2,2'-methylene-bis(4-methyl6-t.-butylphenol) 1 Waring blender (a trademark product).

4 The silica-graft polymer mastcrbatch is dropped into boiling water to vaporize the solvent and the polymer-silica masterbatch is recovered iron;I the aqueous serum and dried.

one.

TABLE XII Masterbatch Silica-Eiastomer Grafted With Quaternary Ammonium Groups (Parts by wt.)

Example (A) Silica pigment slurry:

(a) Silica pigment slurry:

Alkaline silica pigment-I (pH 9.4) 200 200 200 200 Dr; solids basis 20 20 20 a er (b) Reactant-aqueous solution:

2% Aluminum sulfate l 2% calcium chloride- 2% barium chloride...

Filter cake" (B) Solution polym groups-Table VII:

Example 19... Example 20. Example 24. Example 25 Polymer content Antioxidant I (C) Blending (A) plus (B): Blender, min. (X) X X X (D) Solvent removal: 0

Boiling water (X) X X X Silica separation into water-.. (E) MasterbatchzDried (105 C.) (X) X X X 1 Aluminum sulfate Ali(S04)a-14H20.

I Antioxidant 2,2-methylene-bis(4-methyl-6-t.-butylphenol) Waring blender (a trademark product).

l The silica-graft polymer masterbatch is dropped into boiling water to vaporize the solvent and the polymer-silica masterbatch is recoveredfrom th etarqueous serum and dried.

one-

1 Aluminum sulfate AI2(SO4)3'I4H2O.

1 Waring blender (a trademark product).

I The silica-graft polymer masterbatch is dropped into boiling water to vaporize the solvent and the polymer-silica masterbatch is recovered from the aqueous serum and dried.

4 None.

TABLE XIV Preparation of Polymers with Amine Groups (Parts by wt.)

Example (A) Polymer latex:

Recipe:

2-vinylpyridine. Dimethylaminoethylmethacrylate 2 t.-Butylaminoethylmethacrylate 5 Butadiene-l,3 80 80 80 Potassium persulfate- 1 1 1 1 Mercaptan MTM 1 0. 5 0. 5 0. 5 0. 5 (b) Conditions:

Temperature, C 50 50 50 50 Hours 7 7 6 6 (B) Coagulation:

(a) Poured into:

Isopropanol 900 900 900 900 Antioxidant 9 22. 5 22. 5 22. 5 22. 5 Coagulum: Filtered (X) X X X X Yield, wet cake--- 153 93 144 145 Dried C.) (X). X X X X Yiel 59. 5 45.5 75. 6 71.0 (C) Solvation:

Benzene 535 439 680 639 Hoursl C 12/50 12/50 12/50 12/50 1 A tertiary mercaptan (a trademark product). 3 The antioxidant is 2,2-methylene-bis(4-methyl-6-t.-butylphenol).

TABLE XV Silica-Polymer Masterbatch (Parts by wt.)

Example (A) Silica pigment slurry:

Alkaline silicaSPigment-I (pH 25 25 25 25 Dry solidsba s 2.5 2.5 2.5 2.5 Water... 40 40 40 40 (B) Reacta fetch--- 8 5 8.5 8 5 8.5 (C) Combine Blend (X) X X X X Filter (X) X X X X (D) Polymer solution-Table XIV:

Example 45 50 Example 46-.. i 50 Example 47 5 Example 48 50 Dry solids 5 5 5 5 Antioxidant I 0. 1 0. 1 0. 1 0. 1 (E) Combine (C) and (D): Blend, 4 min 0.5 0.5 0.5 0.5 (F) Solvent removalz oiling water (X) X X X X Silica separation in serum (G) Masterbatch:Dried (105 C.) (X) X X X X 1 Aluminum sulfate Alz(SOi);-14H20.

' Concentration adjusted as indicated.

l Antioxidant is 2,2-methylene-bis(4-methyl-6-t.-butylphenol).

4 Waring Blender (a trademark product).

I The silica-solvated polymer masterbatch is dropped into boiling water to vaporize the solvent and the silica polymer masterbatch is recovere? I and dried.

one.

TABLE XVI Preparation oi Polymers Witth Quaternary Ammonium Groups (Parts TABLE XIX Preparation Solution of Graft Polymer Containing Amide Groups (Parts by wt.)

p Example 53 54 55 so 5 65 66 (A) Polymer solution: (A) Graft elastomer latex:

Example 45 Butadlene-styrene copolymer 1 4 520 520 Example 46 60 Dry solids basis 100 100 Example 47 Water 100 100 113212811515 5 5 5 5g giethlacryliamidm 5 cryam e 3 (B) Quaternization: 011 e h dr ide-. 1 (a) Quaternizing agent: Methyl bromide. 0. 2 0. 2 0. 2 0. 2 zfi fi fi X: i 4 (b) Quaternizing condition: Polymerization;

' lg fi r C 2 Temperature, C 50 50 T5 Time, hrs 4 4 Dry solids, percent 14.5 14. 3 (B) Coagulation:

(a) Poured into:

Isopropanol. 900 Antioxidant (b) Coagul Filtered X) X giiltle cake dried (105 4 TAB LE XVII 9 10 20 (O) Solvation: Slice-Polymer Masterbatch (Parts by wt.) fienfizingfiuv a 354 1736 g ae rs. 1250 1250 Example 1 SBR1502 latex (TS=19.3%). 57 58 59 60 2 1 1 3 x S th 1 bl :11 1 b t 1 11 1 silica p g Slurry: T e an ex an 2, me y one 5(4 me y 6 t u y p eno Alkaline silica slurry-I (pH=8.5-9.5) 25 25 25 25 Dry solids basis 2.5 2.5 2.5 2.5 Water 40 40 40 (P2) 1:R eactant-aqueous solution: 2% aluminum su 9 0 9 0 9 0 9 0 TABLE XX 8 8 (0) Combine d S'l'c -P 1 r M t b t P wt.

Ewi g; I 5% 1 a oy as e a h( a t by 1 er E (D) Polymer solution-Table XVI: Z B E g a ol g2 50 67 as 69 70 xamp e Exampl 55 50 (A) Silica pigment slurry: Example 56 50 Alkaline silica pigment-I (pH 8.5-9.5) 25 25 25 25 filg f tfr i ia solids basis 2. 5 2. 5 2. 5 a s c ac a er Dry solids U. 5 5 5 5 (B) Reagent-aqueous solution: (E) Combine (C) and (D): Blend, min 0.5 0-5 0 5 0 5 2% aluminum sulfate 1 (F) Iigolligrent rerjnowzg; 4 X X x X calcium ehlaride 01 ng wa er s uric aci Silica separation in water (0 (C) C ombine (A) and (B): (G) Masterbatch: Dried (105 C.) (X) n X X X X gland, 1 er 1 Aluminum sulfate Alz(S04)a-14Hz0. (D) Polymer solutionTable XIX: i Antioxidant 2,2-methylene-bis(4-methyl-fi-t-butylphenol). Example 65 50 50 I Waring Blender (a trademark product). Example 66 50 50 The silica-solvated polymer masterbatch is dropped i t b g Wat Dry' solids basis 5 5 5 5 to gadpgrige the solvent and the silica polymer masterbatch is recovered (E) 23;, sulliurkzgidany)..1316. .121Y .i- 2 i..-- .i an e om me an en n 4 None. (F) Solvent removal:

Boiling water (X) X X X X Silica separation in ser G) (G) Masterbatch: Dried (105 C.) (X) X X X X 1 Aluminum sulfate Al2(SO -14H1O. I Waring Blender, a trademark product. 3 None. TABLE XVIII Silica-Polymer Solution Masterbatch (Parts by wt.)

Example TABLE xxr 61 62 63 64 Preparation of Solutions of Polylmersgontaining Amide Groups (Parts y w (A) Silica pigment slurry:

Alkaline silica slurry-I (phH=8.5-9.5) 25 25 25 25 Example Dry solids basis 2. 5 2. 5 2;? 71 72 73 Water (B) Reactant-aqueous solution: (A) Elastomer latex:

25 13??? 51mm 9'6 (a) 3 3 5 360 360 360 111 9 2V2 barium chloride 9.0 Tallow fatt acid sodium salt 10 10 1o 2% calcium chloride 5. 0 Styrene 40 40 40 nnexe X X X x messme m Fifr: x x X x Methacry 10 (D) Iiolymer solution-Table XVI: llggttgscllielrlig-lfigfsafifie. 16g 16g 16% R3316 54 Mercaptan MTM L. Example 55 (b) Polymerization conditions: Example 56 50 Temperature, C 50 50 50 Antioxidant 1 0. 1 0. 1 0. 1 0. 1 Hours-.. 1% 1% 5 "113 mm "5- 5 1w arsa ary so 5 (E) Combination (C) and (D) Blendflmln 0.5 0 5 0.5 0.5 Isopropanol 1, 800 1,800 1,900 (G) sqly ent removal; I Antroxldant 2 2 20 20 Bo ling Water (X) X X X X (b) Coaguium: X X Silica separation in serum Filtered (X) X X (E) Masterbatch: Dried (105 C (X) X X X X lgzliletler cake dried (105 0.). 62)?) 712i 123 1 The antioxidant 15 2,2'-methylene-bis(4-methyl-6-t.-butylphenol). olvation? 1 m7 1 Waring Blender (a trademark product). Benzene 566 643 ,2 50 I The silica-solvated polymer masterbatch is dropped into boiling water Agltated hrs./ 0 12-50 1250 1 to vaporize the solvent and the si11ca-polymer masterbatch is recovered and dried.

4 None.

l A trademark product of mixed C12. C14 and C tertiary mercaptans. a Antioxidant is 2,2-metl1ylene-bis(4-methyl-6-t.-butylphenol) TABLE XXII TABLE XXIV-Continued Silica-Polymer Solution Masterbatch (Parts by wt.) Example Example 82 83 84 85 74 75 76 77 5 (F) 523351135: s glution 'lable XIX: V I v (A) Silica pigment slurry: pl 15 150 150 200 Alkalin S111 ent-I H=s.5- 5 25 25 25 25 y o ds basis 15 15 15 20 Dry $51315 5321??? 2.5 2.5 2.5 2.5 5 3 3 13 Blender 1, mm 1 1 1 1 B nuggga'gfigah'gggmig; Boning water (x5 x x x x 27 51 um 5 11 5 1 9 Silica p t on (0 Z jj 10 (I) Masterbatchz Dried (105 0.) (X) x x x x g 312 4 5 1 Aluminum sulfate A1z(SO4) -14H O. (C) i (A) and 3 Carbon black (a. trademark product). Blend (X) x x X X I Processing oil (a trademark product).

11551, X IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII X X X X Waring Blend (a trademark D) Polymer solution-Table XXI: N0119- Example 71 50 50 15 Example 72 50 Example 73 50 25 21 5 0i 0? 0? n o n g; glfnd 0 and 1321518115 min 1 1 1 TABLE XXV 0 van remove w Boning water up x x X X Preparing Solutions of copay-33s ith Nitrogenous Groups (Parts Silica separation in serum-- (G) Masterbatcb: Dried (105 C.) (X) X X X X Example 1 Aluminum sulfate A1z(S04):-14H20. 86 37 88 89 vAvglt ioxirliaalnt 31s 2,%-eig1ylen-bis(-mghyl-6-t.-butylphenol).

ng eneraaemarprouc. 1 1 6 The silica-solvated polymer masterhatch is injected into boiling water (A) 5 {{fi i to vaporize the solvent and the silica-polymer masterbatob is recovered 25 Tallow sodium soap 5 5 5 5 and dried- Water 180 180 130 180 l None. 3 23 Dimethylaminoethylmethaerylate t.-Butylaminoethylmethacrylate g t i efiu- 8g 8 8 0 ass um persu a e TABLE xxm Mercaptan MTM l 0.5 0.5 0 5 0.5 Silica-Polymer Masterbatch (Parts by wt.) (b) ggglgmeeraitzglton E onditions: 50 5o 50 50 Example Hours 7 7 6 6 (B) Coagulation: 78 79 80 81 (a) Poured into: my 1 5 5 5- 22 2 a": 21 2 5 2 A Silica i eat sl 11 0X an Alkalir e l iea pigment-I (pH =8 59 5) 25 (b) Coagulum:

Dry solids basis 2.5 2.5 2.5 2.5 Filtered (X)-. X X X X ate! 1 H 27 alumj I 40 40 40 1g: 2;: 1% 1%? (B) Rea gentaqueous so u on. a num s 8-5 8.5 8.5 8i 59.5 5 75- 6 71-0 (0) :l l i (B): x X X 535 414 080 630 D x x x Hoursl 0 .IIIIIIII 12/50 12 12 50 12 50 Philiwi ell s 1 5 5 1 A tertiary mercaptan (a trademark product). Thermax 1 5 1 The antioxidant is 2,2-methy1ene-bis(4-methyl-6t.-butylphenoi). Statex 160KB 1 5 (E) Processing oil: Circosol 2XH l 0. 6 0. 6 (F; Combine (A) with (D) and (E): Blender, min 1 1 1 1 0 Solution of polymer-Table XXI: 4 Example71 150 150 gxamplezg 150 150 TABLE XXVI Silica-Solution Polymer Masterbatoh Including Carbon Black and 4.67 aqueous ammonium dry solids 15 15 15 15 (H) Blnd (F) and (D): Blender, 1 min 1 1 1 1 Pmcessmg (Parts by (I) Solvent removal: I Exam 1 Boiling water (X X x X 50 P Silica and/0r black separation into serum 9o 91 92 93 (I) Masterbatch: Dried 105 0.) x X X X (A) Silica i ment slurry: :Aluminum Sulfa M2604) EH20 Alkalir e silica pigment-I (pH=8.5-9.5) 25 25 25 25 Carbon black (trademark product). Dr solids basis 2 5 2 5 2 5 2 5 25.3 5 1 3 3 gg gg- 5 5'5 :10 15 :10

n on er a a emar pr uc i The si ca-solvated polymer master-batch is injected into boiling water (B) g figfig gg fi iollutiom 8 5 to vaporize the solvent and the silica-polymer masterbatch is recovered g gg e 4 5 l l g 2% calcium chloride 5 0 (C) Combine (A) and (B):

Blend, (X)----------- X x X X Filter, (X) X 1.--- X X (D) lghaii'gfnkblgcgl and processing oil: 5 5

a0 TABLE XXIV Statex 160HR 1 5 5 Silica-Polymer Masterbatch (Parts by wt.) gzog e s s i ng fii lg umlfi 0. 5

Example Example 8 l 150 Example 87 150 82 83 84 85 Example 88 150 Example 89 150 (A) Silica pigment slurry: Dry solids basis 15 15 15 15 Alkaline silica pigment-I (pH=8.5-9.5) 25 25 25 75 (G) Combine (D), (E) and (F): Blend, min 0.5 0.5 0.5 0.5 5'15" 18 :13 Z58 5 89532 5251??? x x X x H I (B) Reagent-aqueous solution: Silica and black separation in serum. g, aliliminum si li ate .'5 9.0 18.0 (I) Masterbatch: Dried (105 C.) (X) X X X X ca cium n e (C) dombine (A) and (B): 1 Aluminum sulfate Ah(SO4)3-14Hz0.

Blend, (X) X X X 1 Carbon black (a trademark product). tar, (X) X X X Processing oil (a trademark product). (D) Carbon black: 4 Waring Blender (a trademark product).

Statex IGOHIR 5 The silica-solvated polymer masterbatch is dropped into boiling Philblacko 5 water to vaporize the solvent and the silica-polymer masterbatch is Thermax I 5 recovered and dried. (E) Processing 011: Oircosol 2X11 0.5 2.5 None.

TABLE XXVII Silica-Polymer Solution Masterbatch Including Carbon Black and Processing Oil (parts by wt.)

Example (A) Silica pigment slurry:

Alkaline silica pigment-I (pH=8.5'9.5)- 25 25 25 Dry solids basis 2. 5 2.5 2 5 2.5 Water 30 30 3 30 (B) Reactant-aqueous solution:

aluminum sulfate l 8. 5 2% sulfuric acid 4.5 2% calcium chloride- 2. (B) Combine (A) and (B):

Blend, (X) X X X X Filter, (X) X X X X (D) Carbon black Philblack O I 5 Statex 160KB 7 5 5 (E) Processing oil:

Sundex 2X11 0 5 (F) Polymer solution-Table XVI (D)Table XVI:

Example fi' Example 54 150 Example 55 150 Example 56 150 Dry snlids 15 15 15 15 Antioxidant 0.3 0.3 0.3 v 0.3 (G) Blend (C), (D), (E) and (F):

Blend min 0.5 0.5 0.5 0.5 (H) Solvent removal:

Boiling water (X) X X X D Silica and black separation in serum- (I) Masterbatch: Dried (105 C.) (X) X X X X 1 Aluminum sulfate Al2(SO4) -14H O.

1 Carbon black (a trademark product).

Processing oil (a trademark product).

4 Antioxidant is 2,2-methylene-bis( i-methyl-6-t.-butylphenol).

l Waring Blender (a trademark product).

The siiica-solvated polymer masterbatch is dropped into boiling water to vaporize the solvent and the silica-polymer masterbatch 13 recolgered and dried.

one.

TABLE XXVIII Silica-Elastomer Masterbatch Including Processing Oil and/or Carbon Black (Parts by wt.)

Example (A) Silica pigment slurry-treated with carbon black and/0r processing oil:

(a) Silica pigment slurry:

Alkaline silica pigment-I (pH=8.5-9.5) 200 Dry solids basis 20 Water 200 200 20 20 50 (b) Reactant-aqueous solution:

uri a sulf 0 old 6.8 6.8

1 Filter cake after washing.

1 Sundex 2XH (a trademark product).

I States K (a trademark product).

4 Waring Blender (a trademark product).

a The antioxidant is 2,2-methylene-bis(i-methyl-G-t.-butylphenol) Waring Blender (a trademark product). 3

The silica-graft polymer masterbatch is dropped into boiling water to vaporize the solvent and the polymer-silica masterbatch is recovered ro rrlrI the aqueous serum and dried.

one.

The masterbatches prepared in accordance with the present invention may be compounded with vulcanizing ingredients and vulcanized by any suitable recipe (e.g. the recipe set forth in Table I, above) to form useful vulcanizates.

From the foregoing disclosure, it will be appreciated, inter alia, that the present invention improves elastomersilica pigment masterbatches by forming the same with elastomers provided with certain substituent groups improving the compatibility of the elastomer with the aqueously wet silica pigment. I

In certain co-pending applications filed concurrently herewith, different modes of improving elastomer-silica pigment masterbatches are provided by employing wet silica pigment rendered more compatible with elastomers by combining with the wet silica pigment certain conditioning materials.

To maintain clear lines of division between the copending applications the claims of this application recite, and rely for patentability on, only its own improvements, without prejudice to their applicability to processes or products employing such improvements along with a different improvement disclosed in one of said co-pending applications.

Also, while there have been described herein what are at present considered preferred embodiments of the invention, it will be obvious to those skilled in the art that modifications and changes may be made therein without departing from the essence of the invention. It is therefore understood that the exemplary embodiments are illustrative and not restrictive of the invention, the scope of which is defined in the appended claims, and that all modifications that come within the meaning and range of equivalents of the claims are intended to be included therein.

I claim:

1. A process for the curbing of silica pigment losses and the promotion of uniformity of product in the preparation of a silica pigment-elastomer masterbatch from (a) aqueously wet silica pigment and (b) a solvent dispersion of elastomer, which process comprises the steps of:

(c) providing 5 to parts by weight, dry basis, of aqueously wet hydrated silica pigment precipitate which has a bound alkali content in the range of 0.1 to 10% by weight as Na O; which has been prepared by precipitation from an aqueous solution of alkalimetal silicate with the aid of carbon dioxide; and which has continuously been maintained in an aqueously wet state without having been dried therefrom after its precipitation;

(d) providing an organic solvent dispersion containing 100 parts, dry basis by weight, of elastomer, said elastomer containing 0.1% to 20% by weight of nitrogen in the form of substitutent groups selected from the primary amine, secondary amine, tertiary amine, quaternary ammonium, and amide groups and being essentially free of hydroxyl groups; and said solvent being essentially water immiscible;

(e) providing, when used in step (f), reactant selected from the class consisting of the members of the following groups: Group (I), the water soluble salts of aluminum or zinc; Group (II), the water soluble salts of the alkaline earth metals; Group (III), the water soluble acids; and Group (IV), combinations of any two or more members of the foregoing groups;

|(f) combining the wet silica pigment provided by step (c) with from 0 to at least a stoichiometric equivalent, based on the alkalinity of the silica pigment, of reactant provided by step (e); thereby to provide 5 a wet silica pigment for use in step (g);

(g) intimately mixing (1) the wet silica pigment provided for use by step (f), (2) from 0 to 75 parts by weight of carbon black with the limitation that the total of silica pigment and carbon black, dry basis, not exceed parts by weight, (3) from 0 to 45 parts by weight of processing oil, and (4) the solvent dispersion of nitrogenous elastomer provided by step (d), and

(h) separating the volatiles from the resulting masterbatch.

2. A process for preparing a masterbatch from wet 75 silica pigment and a solvent dispersion of elastomer as claimed in claim 1, wherein the solvent dispersion provided in step (d) is a dispersion of grafted elastomer prepared from a solvent dispersion of precursor elastomer by adding to such solvent dispersion of precursor elastomer at least 0.1% by weight, based on the precursor elastomer content, of nitrogen in the form of vinylidene monomer material selected from the vinylidene mono mers that are primary amine, secondary amine, tertiary amine, quaternary ammonium or amide compounds, and polymerizing said grafting monomer material.

3. A process for preparing a masterbatch from wet silica pigment and a solvent dispersion of elastomer as claimed in claim 1, wherein the solvent dispersed elastomer provided in step ((1) comprises quaternary ammonium groups.

4. A process for preparing a masterbatch from wet silica pigment and a solvent dispersion of elastomer as claimed in claim 1, wherein the solvent dispersed elastomer provided in step (d) comprises amine groups.

5. A process fior preparing a master batch from wet silica pigment and a solvent dispersion of elastomer as claimed in claim 1, wherein the solvent dispersed elastomer provided in step (d) comprises amide groups.

6. A process for preparing a masterbatch from wet silica pigment and a solvent dispersion of elastomer as claimed in claim 1, wherein the solvent dispersed elastomer provided by step (d) is prepared with vinylidene monomer material selected from the monomers which are quaternary ammonium compounds.

7. A process for preparing a masterbatch from wet silica pigment and a solvent dispersion of elastomer as claimed in claim 1, wherein the solvent dispersed elasto- 'oombined with the wet silica pigment and nitrogen group containing elastomer in step (g) at least 5 parts by weight of processing oil.

9. A process as claimed in claim 1, in which there is combined with the wet silica pigment and nitrogen group containing elastomer in step (g) at least 5 parts by weight of carbon black.

References Cited UNITED STATES PATENTS 3,244,660 4/ 1966 Herold 260-29i7 2,964,490 12/1960 Howland 26041.5 3,172,726 3/1965 Burke et al. 23182 3,250,594 3/1966 Burke et a1. 23182 3,085,074 4/1963- Burke et a1. 26029.7 2,821,232 1/1958 Wolf 152330 3,081,276 3/1963 Synder 26033.6

MORRIS LIEBMAN, Primary Examiner I. H. DERRINGTON, Assistant Examiner US. Cl. X.R.

26041 A 41 R, 41.5 A, 41.5 R, 41.5 MP 

